Research On The Visualization Of Three-Dimension Contour Line

Geographic information system (GIS) is a space information system that was brought forward in 1960's and developed as time goes by. It is a system that includes data collection, data store, data management, data analysis, etc. It also describes the total earth, the part of earth surface, the coherent data between space and geographic distribution. GIS can realize visualization of geographic information by the form of electron map. It has the dynamic characteristic and interactive feature. So that can provide convenience for using maps. The research on 3D visualization system of geographic information is a hotspot in the research of GIS and it is the basic requirement in many application fields.It can trace back to the century of 18 that using contour express topographical relief. It is deemed that contour is the important invention in the history of mapping for using convenience and visual representation. The visualization researchof 3D terrain & landforms is an important part of geographic information system (GIS), digital photography (DP) and remote system (RS). Contour is the specific linearity factor in GIS. The expressing method of contour can widely apply in all kinds of maps and GIS. At the same time, it is the habitual way that express 3D object using the 2D means.This paper studies basic theory and methods of 3D contour line visualization. The major content of this paper includes the gain methods of discrete data, model building of 3D display of contour line. In the modelling methods, it discusses Grid model and TIN model. During the TIN generating, it puts emphasis on analysis and treatment discrete data using Delaunay triangular net. Finally, based on the analysis of OpenGL, studies on the 3D visualization of contour line.